Properties of processed fats and oils for foods represented by margarines and shortenings vary depending on the kind of the raw fat and oil composition and the kind of the emulsifier used. Such processed fats and oils are also required to have various performances according to their uses.
Baked confectioneries including cakes, cookies, and biscuits are produced mainly from wheat flour, sugar, an egg component, water, fat and oil, etc. In a generally employed process for producing these baked foods, a dough is first produced by the so-called "sugar batter" process comprising mixing fat and oil with sugar, whipping the mixture, gradually adding eggs thereto to form an emulsion, and then mixing the emulsion together with wheat flour. This dough is then molded into an appropriate shape and baked.
The qualities required for baked confectionery include a satisfactory in the degree of baking, internal texture, surface marks of bubbles, meltability in the mouth, etc. In addition, performance requirements necessary in processes for producing, for example, cookies include easiness of creaming in the step of mixing a margarine, shortening, or the like, with sugar, moderate emulsifiability and dough stability in the step of adding egg whites, dough stability after wheat flour addition, and the spreadability of the dough.
To make improvements in such requirements, a technique for enhancing the emulsion stability of a margarine with whole eggs by adding an acetylated sucrose-fatty acid ester to the margarine is discussed in JP-A-59-25645. (The term "JP-A" as used herein means an "unexamined published Japanese patent application.") In JP-A-62-186745 is discussed a highly egg-absorbing fat and oil composition containing a sucrose unsaturated fatty acid ester having an HLB of 5 or lower. Further, another highly egg-absorbing fat and oil composition is discussed in JP-A-63-287438, which contains a combination of a propylene glycol fatty acid ester and another fatty acid ester.
With the recent trend toward higher grades and diversification in the tastes of consumers, the taste for baked confectionery is shifting from baked foods produced using whole eggs to baked foods produced using whole eggs enriched with egg whites or using egg whites alone. For example, baked foods such as langue de chat cookies, French balls, and egg white cakes are characterized, e.g., by the color tone thereof which is free from yellowness due to a reduced proportion of egg yolks or non-use thereof or which can be a bright hue when a coloring ingredient has been incorporated; by a feasible reduction in the content of cholesterol, which is contained in a large amount in egg yolks; and by the cost advantage due to use of egg whites, which are more inexpensive than egg yolks, as the main egg component.
However, with respect to the conventional baked confectioneries produced using egg white-enriched whole eggs or using egg whites alone as the only egg component, processed fats and oils do not sufficiently satisfy the desired performances.
In producing baked confectioneries containing whole eggs, the dough has satisfactory stability and is free from the separation of an egg component therefrom whether wheat flour has been incorporated or not, because lipids such as yolk lecithin contribute to emulsification of a mixture of fat and oil, the egg components, and other ingredients. In contrast, in producing egg white-enriched baked confectioneries, dough stability is difficult to ensure because of insufficient emulsification, and also the dough is reduced in gas-holding property, which is important for increasing the volume of baked foods. In addition, there are problems, for example, that egg white separation from the dough occurs to cause unevenness of baking, that dough sagging occurs during baking to impair the shape of final products, that the baked foods obtained have a rough surface texture, and that scorching begins too early due to excessive water elimination to impair the value of the baked goods.
Dough stability is important in the production of baked confectionery, especially in the case of the so-called langue de chat cookies and the like for which thin dough shaped to about 2 mm thick is baked.
A further problem is that when powerful mixing is carried out for homogenization, the amount of the egg white separated from the emulsified fat and oil is too small and, hence, transfer of water to the wheat flour added later becomes insufficient, so that water elimination from the dough becomes insufficient and this tends to result in half-baking.